Location
The Homestake Mining Company of California (Homestake), Grants Reclamation Project (GRP) is located in Cibola County, 5.5 miles northeast of Milan, New Mexico and approximately 6.4 miles north of Grants, New Mexico.
Ownership and History
Homestake is owned by Barrick Gold Corporation. The Homestake mill operated from 1958 until 1990. The site includes two tailings disposal areas, groundwater remediation systems including a reverse osmosis water treatment plant, and impacted portions of underlying and downgradient groundwater aquifers. Originally, there were two uranium mills that operated independently with separate tailings piles. In 1961, the two milling facilities were combined into one milling operation. Approximately 1.2 million tons of tailings were placed in the Small Tailings Pile and 21 million tons of tailings were placed in the Large Tailings Pile. Milling ceased in 1990 and mill decommissioning and soil reclamation activities started in 1993.
The Atomic Energy Commission issued a U.S. Nuclear Regulatory Commission (NRC) Source Materials License No. SUA-1471 to Homestake in 1957. In 1974, New Mexico became an NRC Agreement State, which granted it the authority to regulate uranium milling activities. The state of New Mexico was responsible for licensing and regulating uranium milling operations at the site from 1974 to 1986. In 1986, New Mexico relinquished authority back to the NRC, which is now the lead regulatory agency for the site. However, the site also was listed on the National Priorities List under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) in 1983. The U.S. Environmental Protection Agency (EPA) Region 6 signed a Memorandum of Agreement with the NRC in 1993 to establish roles and responsibilities of both the NRC and EPA. EPA Region 6 is overseeing a Superfund Remedial Investigation/Feasibility Study (RI/FS) equivalency analysis to address groundwater restoration, long-term tailings stabilization, surface reclamation, and site closure, as well as addressing radon concentrations in neighboring communities. Homestake also is regulated under groundwater discharge permit 200 (DP-200) issued by the New Mexico Environment Department (NMED).
Reclamation and Regulatory Jurisdiction
Decommissioning of the Homestake mill site began in 1993 pursuant to the NRC license. Current decommissioning activities include treatment of impacted groundwater, injection of water to control migration of impacted groundwater, sitewide groundwater monitoring, Large Tailings Pile top surface closure, and Small Tailings Pile full closure. Decommissioning and demolition of mill facilities, surface soil cleanup, and Large Tailings Pile side slope reclamation has been completed at the site.
In 2022, Homestake submitted a license amendment request to the NRC for an evapotranspiration cover design for the top surface of the Large Tailings Pile. Homestake is proposing to cover the top surface of the Large Tailings Pile with an evapotranspiration cover in lieu of the currently approved riprap design.
Homestake is conducting groundwater remediation in accordance with the NRC license under a groundwater corrective action program (GCAP) that the NRC approved in 1989. In 2006, Homestake submitted an updated GCAP and a subsequent revision to the GCAP in March 2012 for NRC review and approval. A third revision to the GCAP was submitted by Homestake in December 2019 and updated in November 2020. To date, the subsequent revisions to the GCAP have not been approved by the NRC.
During the 2020 GCAP update, Homestake concluded that it is unlikely that the approved GCAP will be able to restore groundwater to the groundwater protection standards specified in the NRC license. Therefore, Homestake submitted an alternate concentration limit (ACL) application to the NRC in 2022. This application was rejected by the NRC. The NRC required that the GCAP be revised and updated as of June 2023.
EPA is performing a back-diffusion study of groundwater contaminants. Fieldwork for Phase I was completed, and the report received in August 2024 is currently under review. Phase II field work is planned for the end of 2024 with completion in 2025. Phase III will start late 2025 and will be completed by early 2026.
Timeline for Completion of Cleanup Activities
Currently to be determined according to the NRC.
Coordination Between State and Federal Agencies
The state of New Mexico was responsible for licensing and regulating uranium milling operations at the Homestake mill site from 1974 to 1986. The NRC has regulated the mill from 1986 to present after New Mexico relinquished its authority to the NRC.
Decommissioning and groundwater remediation efforts are occurring under the NRC license. Under the Memorandum of Understanding between the EPA and NRC, NRC is the designated lead regulatory agency for tailings disposal area reclamation and closure activities, and EPA is performing a CERCLA-equivalent RI/FS process with Homestake. NMED regulates the site pursuant to DP-200. The NRC, EPA, and NMED are working cooperatively to complete site closure and continue remediation efforts to ensure protection of human health and the environment. Once Homestake meets the decommissioning and groundwater cleanup requirements of the NRC license, the site will be transferred to the U.S. Department of Energy under the authority of the Uranium Mill Tailings Radiation Control Act of 1987 (UMTRCA) Title II, General License for long-term surveillance and maintenance. Title II of UMTRCA (regulated under Title 10 Code of Federal Regulations Part 40, Appendix A) authorized the regulation of commercial uranium mills operations on or after 1978.
In June 2024 Homestake Mining Company requested the NRC to ‘Conduct an Audit of the Groundwater Flow and Contaminant Transport Model’ and to include DOE, NMED, and EPA in the audit process.
Anticipated Funding Requirements
Homestake Mining Company is the Responsible Party, and therefore, is responsible for funding the clean-up and long-term operations and management at the site.
Nuclear Regulatory Commission Documents
To view the NRC documents, click here.
Disclaimer
Site reviews in this report provide the reader with a general history and status of permitted mines and mills. For brevity, they may not provide all relevant details or agency actions related to each site